1. Field of the Invention
The present invention relates to a planar light emitting mechanism, and in particular to a planar light emitting mechanism having a curved Cold Cathode Fluorescent Lamp (CCFL) to eliminate dark zones.
2. Description of the Related Art
With the progress of semiconductor and flat panel display manufacturing technology, conventional Liquid Crystal Displays (LCDs) have been increasingly applied in electronic devices such as notebook computers.
FIG. 1 is a top view of a conventional planar light emitting mechanism of an LCD, wherein a longitudinal Cold Cathode Fluorescent Lamp (CCFL) 3, used as the light source of the planar light emitting mechanism, is disposed on a side of a light guiding plate 1. Light emitted from the Cold Cathode Fluorescent Lamp 3 enters the light guiding plate 1 and then propagates out therefrom. Reference numeral 2 indicates the light emitting region 2 of the planar light emitting mechanism.
The conventional Cold Cathode Fluorescent Lamp 3 has two darker emitting areas 31 at both ends, where the luminance is lower than the average luminance of the overall Cold Cathode Fluorescent Lamp 3, and a brighter effective emitting area 32 at the middle. That is, the ends of Cold Cathode Fluorescent Lamp 3 are darker than the middle. As a result, the light emitting region 2 of the planar light emitting mechanism has two dark corners 21 adjacent to the darker emitting areas of the Cold Cathode Fluorescent Lamp 3. That is deemed a defect for an LCD and must be avoided. Locating the darker emitting areas away from the light guiding plate 1 to eliminate the dark corners by elongation of the Cold Cathode Fluorescent Lamp 3 is not feasible, because the dimensions of the LCD limit the length of the Cold Cathode Fluorescent Lamp 3. Broken lines A and Axe2x80x2 indicate the boundaries of a region in which the Cold Cathode Fluorescent Lamp 3 can extend in length.
To address the disadvantage of the conventional planar light emitting mechanism mentioned above, the present invention discloses a planar light emitting mechanism providing uniform luminance without occurrence of dark zones.
An object of the invention is to provide a planar light emitting mechanism having a curved Cold Cathode Fluorescent Lamp (CCFL) to provide uniform luminance without occurrence of dark zones.
The planar light emitting mechanism in accordance with the present invention comprises a rectangular light guiding plate and a lamp. The lamp is disposed on a side of the light guiding plate, having a brighter effective emitting area and two curved darker emitting areas. The darker emitting areas are adjacent to the corners of the rectangular light guiding plate, wherein the brighter effective emitting area is between the darker emitting areas.
In another embodiment, the light guiding plate has two round corners corresponding to the darker emitting areas of the Cold Cathode Fluorescent Lamp. The round corners of the light guiding plate generate a light gathering effect to increase the intensity of light emitted from the darker emitting areas of the Cold Cathode Fluorescent Lamp. Thus, the light intensity increases at the corners of the light guiding plate without occurrence of dark zones.
A detailed description is given in the following embodiments with reference to the accompanying drawings.